JPS60234187A - Earthquakeproof supporter for pipe, thickness thereof is smaller than diameter - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to seismic support devices for pipes whose wall thickness is small relative to their diameter.

BACKGROUND OF THE INVENTION In fast neutron nuclear reactors, heat generated in the reactor core is typically carried to a steam generator by liquid sodium flowing in the reactor's secondary circuit. This sodium is 500
℃, and this temperature can undergo relatively large changes during the operation of the nuclear reactor. The sodium in the secondary circuit is at low pressure, on the order of a few bars, and flows through large-diameter pipes whose wall thickness is relatively small compared to the pipe diameter. This pipe has a diameter of more than 1 meter, for example, and its wall thickness is only a few millimeters, typically 2011 mm. This can reduce the amount of stainless steel required to make the secondary circuit sealing the sodium at low pressures above atmospheric pressure, and can reduce the stress on the heat source.

The main stresses to which the pipes of the secondary circuit are subjected are due to sudden changes in the temperature of the liquid sodium, vibrations of the secondary circuit during operation of the reactor, or even more so in the case of earthquakes, repeated forces with large amplitudes. .

Such pipes with large diameters and small wall thicknesses have low crush resistance and are subject to large diameter changes resulting from temperature changes in the sodium carried in the pipe. The vibrations and other repetitive forces that these pipes are subjected to, especially
In the area of the fixing points of the equipment, the pipes may deteriorate to a greater or lesser extent and may even be destroyed.

As a result, supporting such pipes in nuclear reactors poses technical problems that are difficult to solve.

In UK Patent Application No. 84-01184 filed by NOVATOMI 1 on 26 January 1984, a rigid collar surrounding a pipe and defining an annular space around the pipe and between this collar and the outer surface of the pipe are disclosed. A supporting device is proposed which consists of an elastically deflectable and deformable annular sector interposed in the support device. This device makes pipe maintenance effective and allows the pipe to be expanded without creating high stresses on the pipe wall. However, such devices are incapable of absorbing vibrations and other repetitive stresses transmitted undamped by the elastically deflecting annular sector.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to reduce the wall thickness relative to the diameter;
An object of the present invention is to provide an earthquake-resistant support device for a pipe whose temperature increases during operation. and a deformable elastic element of annular shape interposed between the pipe and the supporting device, which enables effective maintenance of the pipe and prevents the pipe from being subjected to excessive stress on its wall. Not only can it be expanded without any damage, but it can also absorb vibrations or repetitive stresses transmitted to the pipe.

For this purpose, the collar has at least two rigid sectors arranged in succession to each other with a gap between them, said sectors having at least one end thereof an axis common to the pipe and the collar. The articulation members are complementary to the articulation members provided in the next sector so as to form joints with parallel axes, and at least two consecutive sectors are capable of closing the collar at one end. an annular deformable element connected to the pipe by an elastic joint device and interposed between the collar and the pipe, each of the sectors having at least two consecutive deformable annular sectors; It has a case inside fixed to the sector of the collar, the case is made of knitted stainless steel wire, with a cylindrical support wall with an inner surface having the same diameter as the pipe, and the inner cylinder inner surface of the collar and the support of the case. It has a plurality of parallelepiped pads interposed between it and the outer surface of the wall, and an annular sector deformable by the elastic joint device of the collar is subjected to compression between the collar and the pipe, so that the annular sector has a radius. It is characterized by the ability to exert a directional force.

In order to explain the invention, some embodiments of seismic support devices according to the invention will now be described with reference to the accompanying drawings.

1 and 2 show a first embodiment of the invention, in which a pipe 1 conducts liquid sodium in the secondary circuit of a fast neutron reactor. This pipe, which has a small wall thickness and a large diameter, is fixed to the reactor structure by a collar 2 and a double hanging lug 3 welded to the collar 2.

The collar 2 consists of three rigid annular sectors 2a, 2b, 2c. These annular sectors are arranged successively around and in coaxial relationship with the pipe 1. A gap 4 is provided between the adjacent ends of the two sectors. The annular sector 2a has lugs 5a at both ends thereof.
, the lugs 5a being welded to the outer surface of the annular sector and lying in a radial plane. sector 2b,
2C is provided with lugs 5b, 5c offset in the axial direction 1i11 with respect to the lug 5a at the end portions disposed in opposing relationship with both ends of the sector 2a. Lugs 5b, 5c
has openings, each opening aligned in axis with the opening in the lug 5b, so that a common shaft 6 is engaged with the aligned openings in the two lugs, and this shaft 6 is held in place by the pin 7. Can be fixed. In this way, a joint of rigid sectors 2a, 2b, 2C is created with joint axes parallel to the axis common to pipe 1 and collar 2.

The ends of sectors 2b, 2C that are not connected to sector 2a have lugs 8b, 8c welded thereto, said lugs 8b,
8c has two sets of openings aligned tangentially with respect to the collar 2, respectively. The two lugs 8c, 8b can be interconnected by means of two equal assemblies formed by a screw 10, a nut 11 and a set of Verebill washers 12, respectively, with an elastic connection between the sectors 2b and 20 of the collar 2. Create a department.

The support device also has three annular sectors 14a', 14b, 1
has an annular deformable element formed by 4C,
Each of these sectors is a rigid sector 2a of collar 2
, 2b or 2c and the outer surface of the tube.

Each of the annular sectors 14 consists of a group of parallelepipeds made of woven austenitic stainless steel wire with a case 15 of thin sheet metal whose longitudinal ends are each hooked into a rigid sector of the collar 2. It is formed by Bat Moon 8. The case 15 has a cylindrical wall 17, the diameter of which is equal to the outside diameter of the pipe 1, and the case 5 has two annular side walls 16, which are capable of deforming the sector II of the collar 2. It is notched along the periphery to constitute a lug 20 for hooking to the rigid sector.When hooking the case 15 to the sector of the collar 2, the cylindrical surface 174; becomes coaxial with the t-pipe 1. .

Parallelepiped parallelepiped rivers 8 are interposed in continuous relationship along the circumference of the pipe 1 between the inner surface of the collar 2 and the inner surface of the cylindrical wall of the case 15. 18 and the case 15 each have a length in the axial direction of the pipe 1 that is substantially equal to the length of the collar 2.

1 Pad-18 is formed by braiding and compressing 18% chromium, 8% nickel austenitic stainless steel wire to form a relatively compact elastic body. Such a pad is VIBIlACIIOC
Manufactured and sold by the company.

In order to place the support device in place on the pipe 1",
After hooking the deformable annular sector 14 to the rigid sector of the collar 2 and positioning the collar 2 around the pipe, tighten the assembly around the pipe by screwing in the nut 11 and screw 10. I'm off. In this way, a radial force is exerted on the deformable element 14. These radial forces are thus transmitted from the sectors of the collar 2 to the paras 118 and from the pads 18 to the cylindrical wall 17 of the case 15, which rests on the outer surface of the pipe 1.

Before the sodium reaches pipe 1, annular sectors 2a and 2b, 2 are introduced into pipe 1, in contact with the outer surface of pipe 1.
They are heated to the operating temperature by electrical preheating conductors 21 placed in each case in the axial direction between a and 20.

Furthermore, a conductor for detecting sodium 34 is placed in the lower part of the gap 4.

The expansion of the pipe 1 is absorbed by the deformation of the pad 18 compressed between the pipe 1 and the collar 2, and the radial expansion of the pipe is transmitted by the cylindrical wall 17 of the case 15.

FIG. 3 shows a graph in which the radial forces exerted on the pads 18 are plotted as ordinate and logarithmic coordinates, and the corresponding deformation (radial compression) of these pads as abscissa; In the case of the pipe and support arrangement shown in Figure 2, the pipe has a diameter of 0.90 m and the pad 18 has a thickness of 0.045 m.

In the graph shown in Figure 3, the radial load is given at 10 Newtons and the corresponding deflection is given at 10-'m. During operation, i.e. after tightening of the support device and bringing the pipe l to operating temperature, the load band applied to the pipe is a curve showing the load as a function of the deflection of the band.
It is shown in bold line in the second part. This load zone corresponds to a transition zone of the curve in which the deflection or deformation of the band increases little with load. The support device is thus able to maintain the pipe effectively, and a large increase in load results in less deformation of the deformable support element.

At this level of loading, the shock absorption capacity of the band 18 is also very high, so that the large amplitude vibrations or repetitive stresses transmitted between the equipment and the pipe are mostly transmitted between the collar 2 and the pipe 1. It is absorbed by the intervening deformable elements. This energy absorption is accomplished by the friction of the compressed braided stainless steel wire itself. In fact, austenitic stainless steel itself has a high coefficient of friction and energy absorption at these stress levels is itself very high.

Due to vibrations, such as those associated with earthquakes, expansion effects due to temperature changes of the sodium, induced in part by the action of external stresses, the stresses transmitted to the walls of the pipe 1 during operation of the reactor are within permissible limits. This is because the deformable pad 18 absorbs axial compression in the load zone without significantly increasing radial loads and very effectively damps repetitive forces through friction.

4 and 5 show a second embodiment of the support device according to the invention, and in FIGS. 4 and 5 and in FIGS. 1 and 2 corresponding elements have the same reference numerals. It's good.

In this embodiment, four deformable annular sectors 25 are provided with a gap 26 between the rigid sectors 2a, 2 of the collar 2.
They are arranged 6 below each of b and 2c. Each of these annular sectors 25 has a cylindrical wall 27 whose diameter is the same as the diameter of the pipe, and the collar 2 is attached to the elastic joint device 1
Tightened by 0.11.12? =J When kicked, the cylindrical wall 27 hits the pipe 1. These annular sectors 254;
t:j - Hooked to sectors of collar 2 by inwardly bent lugs 30 as described.

In the gap 2fi between two successive annular sectors 25, two axially extending sleeves 32,33 are arranged 5, which are welded to the outer surface of the pipe 1. There is a space 34 between the strips 32 and 33.
is formed and a pin 35 introduced into an opening passing through the collar 2 over its entire thickness is placed in this space 34. The similar construction of the twelve strips 32,33 allows the support device to be fixed axially to the pipe 1. In this way, displacements of the pipe due to slipping inside the support device are avoided.

Such an axial locking device is particularly suitable for vertically extending pipes 1.

Such a vertically extending pipe is shown in FIGS. 6 and 7, which shows a third embodiment of the device. Figure 1,
Elements corresponding to those described with reference to FIGS. 2, 4, and 5 are given the same reference numerals in FIGS. 6 and 7.

A vertical pipe 1 is arranged inside the collar 2, and the three sectors 2a, 2b, 2C of the collar 2 are provided with two fixed lugs 40. Rigid sectors 2b, 2c of collar 2
is articulated with an axially extending shaft 6 at the sector 2at, as shown above, and the other end is connected by an elastic joint device 10.11, ]2, thus forming a deformable annular sector. 45 can be compressed between the collar 2 and the pipe 1.

As can be seen in FIG. 7, the rigid sector of the collar 2 consists of two transverse flanges 41. of annular shape over its entire length.
It has 42. Thus the obstruction sector 1 of the collar 2 with transverse flanges 41, 42] its inner surface and the pipe 1
An annular space 4B is formed between the pipe 1 and the outer surface of the pipe 1. Since a gap is created between the ends of the flanges 41 and 42 and the outer surface of the pipe 1, the annular space 48 is not completely closed. .

Arranged in the space 48 is a deformable annular sector 45, which sector 45 has a case 46 hooked at its ends to the collar 2 by means of inwardly bent lugs 50, as described above. ing.

Within each case 46 is a parallelepiped pad made of braided stainless steel wire.

Beneath each rigid sector 2a, 2b, 2c of the collar 2 are:
Four 7 deformable annular sectors 45 are arranged, separated by gaps 52.

The strip 53 welded to the outer surface of the pipe 1 fills the gap 1if.
1 52 in the axial direction of the space 48 . The strip 53 has a length slightly shorter than the axial dimension of the annular space 48 . In this way, the support device is maintained axially relative to the pipe by the flanges 41.42 of the sectors of the collar 2, located at each of the ends of the strip 53.

This construction is particularly useful in the case of pipes with vertical axes, as shown in FIG.

The main advantage of the support device according to the invention is that it can effectively secure the pipe while allowing its radial expansion. Furthermore, with the support device according to the invention,
It can absorb vibrations and other repetitive forces experienced by pipes during nuclear reactor operation or in the event of an earthquake.

1. In fixed embodiments, the pipe may be fixed axially to its support.

The scope of the present invention is not limited to the embodiments described herein, but includes any modifications.

Thus, a different number of deformable annular sectors than those described in the second embodiment may be used.

Further, an elastic joint structure different from that described above may be adopted for the rigid sector of the collar.

4) The collar may be used to secure or suspend the pipe to the reactor structure in a manner different from that described above.

The flange of the side wall of the annular sector case may be bent to color 11 and hooked to the color by a method different from the example described in -.

The support device according to the invention is suitable not only for pipes in fast neutron reactor circuits, but also for cases where it is desired to achieve llllj seismic support for thin-walled pipes with large diameters for transporting 'lk bodies with high l crystals. Can be used in any case.

[Brief explanation of the drawing]

1 is a sectional view of a pipe and support device according to a first embodiment of the invention; 9 FIG. 2 is a view in the direction of the arrow in FIG. 1; FIG. 3 is as shown in FIGS. 1 and 2. 4 is a sectional view of the support device according to a second embodiment of the invention; FIG. 5 is a view in the direction of arrow B in FIG. 4; FIG. 7 is a sectional view of a support device according to a third embodiment of the invention in the direction of arrow C in FIG. 6; FIG. ■...Pipe 2...Collar 2a, 2b, 2c-...Rigid sector 14a, 14b
, l 4 C-... Deformable element 15... Case
18...Pad 17...Cylindrical wall 25...Deformable annular sector 10.11.12...Elastic bonding device 0

Claims (1)

[Claims] (]) An earthquake-resistant support device for a pipe whose wall thickness is small relative to its diameter and whose temperature increases during operation, which surrounds the pipe so as to form an annular space around the pipe, and In the above device, the device comprises a collar fixed to equipment for installing a pipe, and a deformable annular elastic element interposed between the collar and the pipe, wherein the collars are arranged in series with each other with a gap between them. having at least two rigid sectors, said sectors having at least one end thereof an articulation in the next sector so as to form an articulation with an axis parallel to the common axis of the pipe and the collar; The members are provided with complementary articulating members, at least two successive sectors being interconnected by an elastic joint device capable of closing the collar at one end and interposed between the collar and the pipe. The annular deformable element is formed by at least two consecutive deformable annular sectors, each of which has a case inside that is fixed to a sector of the collar, the case having the same diameter as the pipe. a cylindrical support wall having an inner surface having;
It is made of braided stainless steel wire, has a plurality of parallelepiped parallelepipeds interposed between the inner surface of the inner cylinder of the collar and the outer surface of the supporting wall of the case, and is deformable by the elastic joining device of the collar. Support device, characterized in that it is possible to compress the annular sector between the collar and the pipe without exerting radial forces on the annular sector. (2) deformable annular sectors are arranged in continuous relationship around the pipe, defining gaps between said deformable annular sectors, and inside each of said gaps, two continuous sectors are formed on the outer surface of the pipe; A strip is fixed in the axial direction of the pipe by welding, defining a space between said two strips, into which the end of the bottle inserted into the opening extending through the collar extends, forming a gap around the pipe. 2. A support device according to claim 1, wherein the pins and strips placed on the support device maintain the pipe axially relative to the support device. (3) The rigid sector of the collar has a transverse flange that laterally limits the annular space formed between the inner surface of the collar and the outer surface of the pipe, the annular sector having a continuous relationship within said annular space. are arranged without gaps, forming gaps between the annular sectors, and within each gap a strip extending in the axial direction of the pipe is fixed to the pipe by welding, said strip having a width slightly smaller than the axial dimension of the annular space. 4. Support device according to claim 1, having a small length and cooperating with flanges of sectors of the collar to maintain the pipe axially relative to its support device. (4) At least one of the rigid sectors of the collar has a lug for suspending or fixing the pipe to the equipment to which the collar is attached. or one support device. (5) A support device according to any one of claims 1 to 4, wherein the collar consists of three rigid sectors.